MX2012001763A

MX2012001763A - Sealing apparatus and method.

Info

Publication number: MX2012001763A
Application number: MX2012001763A
Authority: MX
Inventors: Carl Richard Wood
Original assignee: Nat Oilwell Varco Uk Ltd
Priority date: 2009-09-01
Filing date: 2010-09-01
Publication date: 2012-06-08
Also published as: DK2473701T3; AU2010291006B2; EP2473701A2; GB0915085D0; BR112012004554B1; CN102612588A; CA2769694C; WO2011027149A2; US20120241663A1; EP2473701B1; SG178297A1; WO2011027149A3; CN102612588B; CA2769694A1; US8770541B2; BR112012004554A2; AU2010291006A1

Abstract

A sealing apparatus and method is disclosed, particularly for sealing around an elongate member which passes through a throughbore of a valve device, the apparatus having an upper sealing element and a lower sealing element, each being adapted to change configuration from an open configuration to a sealed configuration within the valve device to seal the throughbore of the valve device around the elongate member. The upper and lower sealing elements are separate and moveable independently from one another, and are configured to be actuated between open and sealed configurations by a common actuator. This actuation reduces the stack height and the weight of the valve, and reduces the number of well seals.

Description

APPARATUS AND METHOD OF SEALING Field of the Invention The present invention relates to a sealing apparatus and methods, typically for use in fixed line valves, particularly but not exclusively, used in the oil and gas industries. Particularly, the invention is useful in fixed line valves, but it can be applied to other situations where it is required to seal the ring around an elongated member, in the apparatuses typically called blowout preventer valves, or BOP.

Background of the Invention Conventionally, fixed line valves are used to control the drilling pressure during the fixed line intervention operations. Typically fixed line valves press opposite pairs of plunger assemblies against the fixed line to provide a double-security barrier against well pressure while performing corrective work, typically on the wire or line.

Conventionally, plunger assemblies use resilient (eg, rubber) seals mounted on the inner faces of two opposed plunger assemblies within the fixed line valve, to clamp the fixed line cable between the seals, thereby containing the pressure. The inner faces of the seals typically have a depression that molds to the outer surface of the fixed line. Piston mounts and seals move against the fixed line cable, typically from opposite sides of the valve, to close the ring surrounding the fixed line cable. Typically, fat is then pumped into and around the fixed line cable. Resilient seals are supported by plates (typically metallic) in the plunger assemblies which retain the resilient seals in place, resisting the movement of the seals in response to the pressure differential across them. Conventional fixed line valves have two pairs of seals, for example, a pair of upper seals and a pair of lower seals, each seal moves independently by its own actuator (for example, a hydraulic cylinder in most cases) with a grease chamber between the upper and lower seals, allowing the injection of grease into the chamber between them when they are held against the fixed line cable.

Description of the invention According to a first aspect of the present invention, there is provided a sealing apparatus for sealing around an elongated member passing through a through hole of a valve device, the apparatus comprising an upper sealing element and an element lower sealer, each adapted to change the configuration from an open configuration or a sealed configuration within the valve device to seal the passage hole of the valve device around the elongated member, the upper and lower sealing elements that are separated and they can be moved independently of each other, and they are configured to be actuated between open and sealed configurations by a common actuator.

Typically, the upper and lower sealing elements are separated in the valve device, typically by a very small clearance, for example, of less than 5 mm.

The change in the configuration can be a change in the position, for example, a movement, or it can be a change in the form. In typical embodiments of the invention, the sealing elements move from one configuration to the other. In some embodiments, the upper and lower sealing elements may be in contact with each other in their open configuration, and finally they may be separated from one another along the axis of the through hole when switching between the open configuration and the closed configuration. Typically, the sealing elements are separated axially from one another by a small distance when fat is injected therebetween.

Typically, the upper and lower sealing elements each comprise a first and a second seal, for example a left and a right seal, which optionally move in the same plane against the elongated member, typically from opposite directions.

The seals are typically housed in plunger assemblies, which approach the elongate member from opposite directions, optionally in the same plane, and are sealed together. Therefore, a typical embodiment of the invention may comprise two piston assemblies, each piston assembly having two upper and lower sealing elements, which can be moved separately.

The invention also provides a plunger assembly for a fixed line valve, the plunger assembly comprising at least two sealing elements, wherein each of the sealing elements are separate and movable independently of each other, and are configured to be actuated by a common actuator.

Typically, the actuator comprises a hydraulic cylinder. Typically, the sealing elements couple a rod connected to the piston in the cylinder.

According to a further aspect of the present invention, there is provided a method for sealing around an elongated member passing through a through hole of a valve device, the method comprising providing an upper sealing element and a sealing element bottoms separated in the valve device, and each one adapted to change the configuration from an open configuration to a sealed configuration within the valve device to seal the passage hole of the valve device around the elongated member, the sealing elements upper and lower that are separate and that can be moved independently of one another, and actuate the sealing elements between open and sealed configurations using a common actuator.

The upper and lower sealing elements are typically mounted in a common plunger assembly on each side of the elongated member.

In a typical embodiment, the first upper and lower sealing elements (for example, those on the left side) are actuated by an actuator (for example, a hydraulic cylinder located on the left side of the fixed line, and the left seals engage typically by the same stem of the left hydraulic cylinder) and the second upper and lower mechanisms (for example those on the right side) are typically driven by a second actuator (for example a second piston rod separated from a second hydraulic cylinder separated from the first hydraulic cylinder , located on the right side of the fixed line).

In some embodiments, an individual actuator may be used to activate the two seals, instead of the two seals that act on the respective pairs of seals. Where two actuators are used in the same plane, they may be diametrically opposed to one another, or they may be arranged in some other angle that is more or less 180 °. In some embodiments, an individual seal (with two seal assemblies) can be moved from one side, typically under the force applied by an actuator from that side.

The elongate member is typically a fixed line, a register line, cable or the like. In a typical embodiment, the upper and lower sealing elements on each side are arranged in a common single piston assembly, which is actuated by a respective individual actuator on each side.

Typically, the plunger assembly on each side of the valve may have guide arms for guiding and centralizing the fixed line or other elongated member, and the guide arms may optionally intertwine and cooperate with each other to guide the fixed line, etc., in a suitable position in relation to the sealing elements for actuating the actuators to seal with the through hole. In this way, each plunger assembly (left and right) can have a pair of guide arms, and optionally two pairs of guide arms. Typically, the plunger assemblies, left and right, are substantially arranged diametrically opposite each other along the longitudinal axis of the through hole. Optionally, the guide arms are arranged around the adapted depression to accept the elongated member therein.

In one embodiment of the invention, each valve has a longitudinal passage hole for receiving the elongated member (e.g., the fixed line) and the through hole has left and right plunger housings in the form of plunger side holes, which they intersect with the through hole and house the left and right plunger assemblies that move inside the plunger holes in a common plane that is perpendicular to the through hole. Each plunger assembly (eg left and right) has a pair of top and bottom sealing elements. Each of the sealing elements typically has a pair of seals, optionally in the form of inner seals on their radially inner faces, to be supported against the elongate member to seal the through hole, and an outer seal typically housed in a slot, which it can be annular or partially annular, and typically seals the ring between the plunger holes and the plunger assemblies. Typically, the inner and outer seals in each sealing element are connected to complete the seal. However, it is not necessary for the seal on each side to move, and in some modes only an individual seal can be moved on one side.

Typically, the plunger assemblies and optionally the seal assemblies are resistant to rotation within the plunger holes. Typically, the plunger assemblies and optionally the sealing assemblies are not circular, and thus resist rotation.

In one embodiment, at least one of the sealing elements (and typically both of these) can be moved relative to the common actuator, and this is typically achieved by a limiting connection between the actuator and the sealing elements.

As an example of a limiting connection between the sealing elements and the actuator, the radially outermost assembly of each of the piston assemblies in one embodiment each typically has a channel, slot or axial opening in which a portion of the piston is captive. actuator (e.g., a head or spike), but is limited to moving axially along the length of the channel, groove or opening, which typically may be coaxial with the axis of movement of the sealing element. The actuator portion can only move within the confines of the opening, and is typically axially shallower than the opening, to allow relative axial movement between the two, but to restrict or negate relative and optionally rotational lateral movement. In one embodiment, the actuator portion may comprise a T-shaped head on the part of the actuator, and the head may be located in the channel, slot or opening. A typical actuator comprises a hydraulic cylinder, usually located within the plunger bore, but the particular design of the actuator is not important, and a mechanical screw actuator can be used in place of a hydraulic cylinder, if desired.

The channel at the radially outermost end of the plunger assembly typically accepts the captive portion that is optionally in the shape of. A T-shaped head on the shank of the hydraulic cylinder, and retains the T-shaped head inside the channel by means of a lip on the inner surface of the channel, which prevents the T-shaped head from leaving the channel. The channel can be a simple depression formed on the opposite faces of the upper and lower sealing elements of the piston assemblies, and the depressions in each of the upper and lower sealing elements can typically be aligned to form the channel therebetween, allowing them in this way they are mounted around the head of the rod and retain the head in the channel.

Typically, the channel may have a neck for receiving the stem, and the neck may have a diameter narrower than the head, thereby allowing the stem to pass through the neck but retaining the head within the confines of the channel. The depth of the channel in the axial direction of the head movement typically has a dimension greater than the depth of the head, so that the head can travel within the channel for a small distance before joining the neck stop at the outer end of the channel or the wall of the sealing element at the inner end of the channel. The desired limitations to the movement in each case are typically related to the resilience and size of the inner seal, and the axial distance that the head can move within the channels is different depending on the different characteristics of the inner seal, which can vary in different cases and it is not proposed that it be a limiting feature of the invention. For example, in some cases, for example with small seals adapted to retain a thin fixed line with a very narrow hole, the axial travel distance of the shank head can be for example 2-3 millimeters, but in larger valves with seals larger and / or more resilient, the axial travel distance can be for example 10-15 mm.

The channel is typically formed of two semi-circular depressions machined at the outer ends of the bodies of the sealing elements, which cooperate to form the channel, and retain the head of the stem. The body of either of the two sealing elements can therefore move independently of the other in the plunger assembly, relative to the actuator, while the other remains stationary and coupled with the T-shaped head of the shank. Accordingly, the sealing elements can react independently of one another to pressure differentials through the seals, by means of the loose adjustment of the actuator and the piston assembly. The loose fit of the shank in the channel is typically restricted so that the sealing elements are not completely free to move in each plane, and typically the range of motion is restricted, for example, to the axial movement of the sealing elements relative to the shank , in the direction of movement of the rod during the drive. Typically, the sealing elements are captive in plunger holes and are restricted to move only along the axis of the holes, which is typically parallel to the axis of movement of the actuator during actuation.

Typically, the sealing elements comprise seals mounted on seal bodies to support and orient the seals. The seal bodies typically have faces or outer surfaces for coupling the inner surfaces of the plunger holes, and typically have faces or mating surfaces, which may be flat, and which may optionally be coined together, e.g. some embodiments, to guide the sliding movement of the sealing elements with respect to each other. Seal bodies typically have grooves formed in the mating faces or surfaces to form the channel for receiving the head of the rod. In certain embodiments of the invention, the seal bodies may have grease channels extending axially (eg, parallel to the plunger hole) from the inner end of the seal bodies to the outer end of the seal bodies for providing an axial channel for the injected grease to pass from the outer face or surface of the sealing elements typically between the coupling surfaces of the seal body in order to reach the fixed line held between the inner seals. The axial grease channel can optionally comprise an axial groove formed in one of the coupling surfaces of the seal bodies, or it can optionally be provided on both faces or surfaces, and in that case, optionally the two grooves can then be overlapped by an axial groove. to the other to form a larger conduit for fat. The grease channel can optionally end in the groove that the stem receives. Optionally, a grease channel can be provided in one or in each of the seal bodies. The grease channel has typically provided a path of low grease resistance injected behind the sealing elements to allow effective penetration of the fixed line cable trapped between the inner seals. Of course, free-form fat can optionally be injected between the sealing bodies without providing any particular fat channel.

The apparatus typically has a grease injection device for injecting grease between the sealing assemblies, upper and lower. The grease injection pressure typically applies additional pressure on the sealing elements to energize the seals, and typically can move one or both of the sealing elements relative to the stem and / or relative to the other sealing element.

The upper and lower sealing elements are typically oriented in different directions, to resist pressure differentials in different directions, for example, opposite.

Actuation of the upper and lower sealing elements from a common actuator reduces the stacking height and weight of the valve, and reduces the number of well seals.

Now embodiments of the present invention will be described, by way of example only, with reference to the appended figures, in which: Figure 1 is a perspective view of a fixed line valve incorporating the sealing apparatus of the invention; Figure 2 is a perspective cut-away view of a simplified view of the valve sealing apparatus in Figure 1; Figure 3 is a side view of the sealing apparatus of Figure 2; Figure 4 is a side view of a pair of left and right plunger assemblies of the sealing apparatus; Figure 5 is a perspective view of the plunger assemblies of Figure 4; Figure 6 is a front view of the apparatus of Figure 2 in an open configuration; Figure 7 is a front view of the apparatus of Figure 2 in a closed configuration; Figure 8 is a front view of the apparatus of Figure 2 in a closed and pressurized configuration; Figure 9 is an approach view of Figure 8; Y Figures 10, 11 and 12 are side sectional views of the valve of Figure 1 in open, closed and pressurized positions, respectively.

Figures 1, 10 and 12 show a fixed line valve V for use with fixed line cable (not shown) in an oil or gas well. The fixed line valve V is typically used to close the valve passage hole 2 to hold the pressure below in the well.

The valve V has a body 1 shown in the sectional view in Figure 2, which has a vertical passage hole 2 through the body 1 for communication with a perforation of an oil or gas well. The through hole 2 has an upper hole 5u and a lower hole 51, and typically accommodates a fixed line (not shown) passing between the holes 5u, 51, and extending generally along the central axis 2x of the hole in step 2. The body 1 has a pair of three lateral plunger holes that connect the vertical passage hole 2 with the left and right sides of the body 1. The piston holes 3 each house a piston assembly 5 in the holes 3 on the right and left, respectively.

The plunger assemblies 5 in the left and right holes are substantially similar to each other, and are pushed axially through the plunger holes 3 by actuators. In this embodiment, the actuator is in the form of a rod 6 that moves axially through the plunger bore 3 by a suitable impeller, such as a hydraulic cylinder 4. The particular type of impeller is not important, and the modes of The invention can work satisfactorily with mechanical or other impellers, for example, those that depend on screw threads. The rod 6 has a head 6h.

Each plunger assembly 5 has a suppressive sealing element 10 and a lower sealing element 20, as shown in Figures 4 and 5, by way of example. The cross sections of the upper and lower sealing elements 10, 20 are substantially symmetrical about the plane through which the axis of the plunger hole passes.

The upper sealing element 10 has a body 12 of a generally semi-cylindrical shape, with an axis that is generally parallel with an axis of the piston hole 3 in which it is housed. In this particular embodiment, bodies 12 and 22 generally have semioval shapes, as best shown in Figure 3, although other shapes may also be used. The body 12 is typically made of steel or another metal and supports the seals as will be described later. The body 12 has an inner end, an outer end, and an arcuate upper surface or face extending therebetween has a partially circumferential seal groove 14 in which an outer seal 16 is located., and a flat, lower face or surface. As shown in Figure 4, the outer seal 16 extends around the arcuate upper surface of the body between the inner and outer ends, and as shown in Figure 2, seals against the inner surface of the piston side hole 3. The recessed seal groove 14 supports the seal 16 against axial movement in the piston bore 3 or other collapse under high pressure differentials.

The body 12 also has an inner seal groove 15, which houses an inner seal 17 at its axially inner end, so that the inner seal 17 is located closer to the passage hole 2 of the valve 1. The inner seal 17 is optionally attached by two metal plates that are attached to the rubber portion during the manufacturing process, although a simple rubber block may suffice. The inner seal 17 in this embodiment is supported above or below by metal plates that place limits on the degree to which seal 17 can be deformed during exposure to pressure differentials, and in this mode it is fixed to plates with bolts or other assemblies. The innermost face of the inner seal 17 has a depression 18 which is arranged to be perpendicular to the longitudinal axis of the cylindrical plunger body 12, and which is arranged to be aligned with the axis of the through hole 2 in use.

Optionally, the body 12 has fixed line guides 19 at its inner end that provide "V" shaped guiding formations that guide a fixed line in the depression 18.

At its outer end, opposite the inner seal, the body 12 has a depression, which typically is in the form of an opening or slot or channel. In this case, the depression 13 extends axially in alignment with the axis of the shank 6. The depression 13 is machined on the flat underside, and typically has two portions, a deep groove with a wide diameter, and a lip with a restricted diameter (typically smaller than the diameter of the head 6h of the rod 6).

The lower sealing element 20 has a cross section similar to the upper sealing element, and has a body 22 in general of a semi-cylindrical or semioval shape of steel or other metal supporting the seals. The body 22 has a lower arcuate face having a partially circumferential seal groove 24 in which an outer seal 26 is located. Like the seals in the upper sealing member 10, the outer seal 26 in the lower sealing element 20 extends around the lower arcuate surface of the body as shown in Figure 4, and as shown in Figure 8, seals against the inner surface of the plunger bore 3. A recessed seal groove (similar to slot 14) supports seal 26 against collapse under high pressure differentials. The left and right lower seals 20 are not identical to each other, and are arranged to fit together to enclose and support the inner seals 27, to press them together. In reality, the lower sealing element 20 on the right is optionally substantially the same as the upper sealing element 10 on the left.

The body 22 also has an inner seal groove (similar to the seal groove 15) which houses an inner seal 27 at its inner end, relative to the piston bore 3, located closer to the bore 2 of the valve 1 The inner seal 27 typically has the same construction as the inner seal 17.

Optionally, the body 22 has fixed line guides 29 that provide "V" shaped guiding formations that guide a fixed line in the depression 28. The guides 29 typically cooperate with the guides 19 in the upper sealing element 10 to guide the fixed line in depressions 18 and 28, which align with each other to seal around the fixed line or other elongated element.

As best seen on line 9, the arrangement of the seal grooves in the bodies 12 and 22 ensures that in the drive to the sealed configuration, the seals 16 are pressed against the seals 17 and the seals 26 against the seals 27, thereby connecting the inner and outer seals in each sealing element 10, 20 and creating a pair of sealed wraps around the fixed line supported by the seals in use.

The lower body 22 also typically has a depression 23 in alignment with the axis of the rod 6 at its radially outer end, and in alignment with the depression 13 in the body of the upper sealing element. The depressions 13 and 23 combine to form a hole for receiving and retaining the head 6h of the rod 6 at the outer end of the sealing elements 10, 20. The hole is formed by the juxtaposition of the semicircular depressions 13, 23 in the bodies upper and lower sealers 12, 22 symmetrical.

The left and right piston assemblies 5 each comprising the upper and lower sealing elements 10, 20 are placed within the respective piston holes 3 to the left and right of the fixed line valve 1, and in the normal operation of The fixed line valve, the pair of plunger assemblies 5 will be located in the position shown in Figure 6 such that they are not interfering with the through hole 2 of the fixed line valve 1. However, when intervention is required, such that sealing is required between the fixed line at the point where it passes through the passage hole 2 of the fixed line valve, then the plunger assemblies 5 are pushed one toward the another by the hydraulic cylinders 4 acting on the rods 6 on the left and right which are coupled to the respective left and right piston assemblies 5 by means of the channels 13 that retain the heads 6h of the pistons 6.

The left and right pistons 5 approach each other under the force applied by the rods 6, as shown in Figure 7 and are arranged such that the fixed line guides 18 and 28 are in a sliding fit with each other, and inter-assembled , thus ensuring that the fixed line will be picked up by the arrangement of the fixed line guides 18, 28 and as the left and right piston assemblies 5 move toward each other, the fixed line will be guided until it is located in the aligned depressions 19, 29 formed between the inner seals 17, 27.

The plunger assemblies 5 continue to move towards each other until the inner seals 17, 27 are pressed together, which also press the outer ends of the inner seals 17, 27 against the adjacent ends of the outer seals 16, 26. In this way , the leakage routes surrounding the upper hole 5u are sealed by the seals 16, 17 in the upper sealing element 10 and the lower orifice 51 is sealed by the seals 26, 27 in the sealing element 20, and in each case the seals Inside and outside are connected to seal completely around the hole, thus ensuring that the pressure in the bore is retained below the fixed line valve by the two complete barriers (upper and lower).

The fat is typically injected between the upper and lower sealing elements 10, 20 under high pressure, typically at a higher pressure than the pressure of the perforation to which the valve is rated to retain. For example, where the fixed line valve is rated at 10000 psi (703.07 kg / cm2), it is used where the drilling pressure is typically less than this, and a typical drilling pressure for this valve may be around 8000 lb / in2 (562.46 kg / cm2). The fat is typically injected into the plunger bore 3, behind the outer seals 16, 26 at a pressure that is approximately 10-20% greater, for example, 10,000 psi (703.07 kg / cm 2). The rod 6 is not sealed to the piston assemblies 5, so that the grease is squeezed out in the space between the inner seals 17, 27 and in the leakage routes within the many wire strands in the fixed line cable. Typically, the sealing elements 10, 20 are initially touching or are closely adjacent to each other in the open configuration, but as the fat is injected in the closed configuration, the sealing elements 10, 20 are typically pushed axially away from each other by the injection of the grease, for a small distance related to the tolerance of the piston assemblies 5 inside the piston holes 3. This is advantageous, since it allows the creation of a small fat chamber between the seals.

Therefore, the pressure differential across the two sealing elements 10, 20 is not equal because the conduit immediately below the valve 1 is 10000 psi (703.07 kg / cm2), and the conduit immediately above the valve 1 is at atmospheric pressure, so that the upper sealing element 10 is exposed to a too large pressure differential than the lower sealing element 20.

Therefore, when the sealing elements 10, 20 are sealed against the fixed line and the grease pressure is applied to pump the grease into the fixed line and to close the leakage paths between the upper and lower holes 5u, 51, the Inner seals 17, 27 are able to move axially within the plunger bores 3 in accordance with the pressure differential to which they are exposed. The force applied to the lower sealing element 20 by the moderate differential pressure through the lower sealing element 20 is not usually sufficient under normal conditions of the perforation to overcome the reaction force of the inner resilient seal 17 which reacts to the pressure of the head 6h of the stem 6 against the lower body 22. Therefore, under normal conditions, the head 6h remains pressed against the radially outer end of the channel 13 while the inner seal 27 in the lower sealing assembly is held pressed against the line cable fixed and against the opposite inner seal 27. However, since the pressure of the passage hole immediately above the fixed line valve V is much lower than the pressure below this, and since the same pressure is applied grease to the hole to penetrate the upper and lower sealing elements 10, 20, the upper sealing element 10 is set to a much larger differential pressure than the lower sealing element 20. Therefore, the same fat pressure behind the outer seals 16, 26 applies more force to the upper sealing element 10 than to the lower sealing element 20. The force applied to the upper sealing element 10 by the pressure differential is greater than the force applied by the hydraulic cylinder 4 and the rod 6, and in this way the upper sealing element 10 is pressed axially against the fixed line cable not by the hydraulic pressure but by the differential of pressure between the injected fat and. the hole immediately above the fixed line valve V.

A benefit of the present arrangement is that in the case of momentary pressure peaks in the perforation below the valve, the high pressure surge below the valve increases the pressure differential applied to the upper sealing elements 10, and this causes that the upper seals move closer together as shown in Figure 9 within the limitations of the head 6h moving axially within the channel 13, so that the inner seals 17 are pressed together harder, self-energizing from this mode the valve seals without external control or external power, as an automatic reaction to the peak pressure of the borehole.

Modifications and improvements can be made to the above embodiments without departing from the scope of the invention.

Claims

1. A sealing apparatus for sealing around an elongated member passing through a through hole of a valve device, the apparatus is characterized in that it comprises: an upper sealing element and a lower sealing element, each one being adapted to change the configuration from an open configuration to a sealed configuration within the valve device to seal the passage hole of the valve device around the elongated member, the upper and lower sealing elements that are separate and move independently of one another, and They are configured to be operated between open and sealed configurations by a common actuator.

2. A sealing apparatus according to claim 1, characterized in that the through hole of the valve device has an axis, and wherein the upper and lower sealing elements are spaced along the axis of the through hole, and are separated from each other. along the axis of the through hole for a distance of less than 5 mm.

3. A sealing apparatus according to claim 1 or claim 2, characterized in that the upper and lower sealing elements are housed in the same hole.

4. A sealing apparatus according to any preceding claim, characterized in that the upper and lower sealing elements change the configuration as they move from one configuration to the other.

5. A sealing apparatus according to claim 4, characterized in that the upper and lower sealing elements each comprise a first and a second seal that move against the elongate member in different directions and in the same plane.

6. A sealing apparatus according to claim 5, characterized in that the sealing apparatus has two piston assemblies, and wherein each piston assembly has two upper and lower sealing elements that can be moved separately.

7. A sealing apparatus according to at least claim 6, characterized in that one plunger assembly is arranged on the left side of the valve device and the other plunger assembly is arranged on the right side of the valve device.

8. A sealing apparatus according to any preceding claim, characterized in that the valve device has a longitudinal through hole for receiving the elongated member and the through hole has piston housings, left and right, in the form of piston side holes , which intersect with the through hole and which house left and right plunger assemblies that move axially within the plunger holes in a common plane that is perpendicular to the through hole.

9. A sealing apparatus according to claim 8, characterized in that the piston assemblies on the left and right side of the valve device are arranged substantially diametrically opposite one another around the longitudinal axis of the through hole.

10. A sealing apparatus according to any of claims 6 to 9, characterized in that each of the upper and lower sealing elements each has a pair of seals in the form of inner seals on their radially inner faces, which are supported against the seal. elongated member for sealing the through hole, and in the form of outer seals, which are housed in a groove of the sealing element, to seal the ring between the plunger holes and the piston assemblies.

11. A sealing apparatus according to claim 10, characterized in that the inner seals have a depression that is arranged to be perpendicular to the longitudinal axis of the piston assembly and which is arranged to align with the axis of the through hole in use. .

12. A sealing apparatus according to any of claims 8 to 11, characterized in that the plunger assemblies are arranged to be resistant to axial rotation within the respective plunger hole.

13. A sealing apparatus according to any preceding claim, characterized in that at least one of the sealing elements can be moved relative to the common actuator.

14. A sealing apparatus according to claim 13, characterized in that a radially outermost end of at least one of the sealing elements has an axial channel in which a portion of the actuator is captive, which is adapted to move coaxially with the axis of the seal. movement of sealing elements.

15. A sealing apparatus according to claim 14, characterized in that the captive portion of the actuator is axially shorter than the channel to allow relative axial movement of the head and the channel when the head is captive within the channel.

16. A sealing apparatus according to claim 14 or 15, characterized in that the channel comprises a pair of depressions formed in opposite faces of the upper and lower sealing elements of the piston assemblies, and wherein the depressions in each of the elements Upper and lower sealers are adapted to line up to form the channel between them.

17. A sealing apparatus according to claim 15 or 16, when dependent on claim 14, characterized in that the channel has a neck to receive part of the actuator that forms a rod, wherein the neck has a diameter narrower than the head.

18. A sealing apparatus according to any of claims 14 to 17, characterized in that one of the two sealing elements can move independently of the other in the piston assembly relative to the actuator.

19. A sealing apparatus according to any preceding claim, characterized in that the sealing elements have seals mounted on seal bodies to support and burst seals.

20. A sealing apparatus according to claim 19, characterized in that at least one of the seal bodies has at least one fat channel extending axially from an inner end of the seal bodies to an outer end of the respective seal body. to provide an axial fat channel.

21. A sealing apparatus according to claim 20, the apparatus is characterized in that it has a grease injection device for injecting grease between the upper and lower sealing elements.

22. A sealing apparatus according to any of the preceding claims, characterized in that the upper and lower sealing elements are oriented in different directions.

23. A sealing apparatus according to any preceding claim, characterized in that the elongate member is a fixed line, a registration line or a cable.

24. A sealing apparatus according to any preceding claim, characterized in that the upper and lower sealing elements are in contact with each other in the open configuration.

25. A sealing apparatus according to any preceding claim, characterized in that the upper and lower sealing elements can be separated from one another along the axis of the through hole when switching between the open configuration to the closed configuration.

26. A plunger assembly for a valve device, the plunger assembly is characterized in that it has at least two sealing elements, wherein each of the sealing elements separates and can move independently of one another, and is configured to be actuated by a common actuator.

27. A piston assembly according to claim 26, characterized in that the sealing elements couple a rod connected to the actuator.

28. A piston assembly according to any of claims 25-27, characterized in that the sealing elements are housed in piston holes in the body, and in which each piston hole contains no more than one sealing assembly.

29. A piston assembly according to claim 28, characterized in that the piston hole is not circular.

30. A method for sealing around an elongated member passing through a through hole of a valve device, the method is characterized in that it comprises: providing a top sealing element and a lower sealing element separated in the valve device, and each one that adapts to change the configuration from an open configuration to a sealed configuration within the valve device to seal the passage hole of the valve device around the elongated member, the separating and upper and separable sealing elements that can be moved independently of one another, and actuate the sealing elements between open and sealed configurations using a common actuator.

31. A method according to claim 30, characterized in that the upper and lower sealing elements are mounted in a common plunger assembly on each side of the elongated member, and wherein the upper and lower sealing elements mounted on one side of the elongate member are actuated by an actuator and the upper and lower sealing elements mounted on the other side of the elongate member are actuated by a second actuator.

32. A method according to claim 31, characterized in that the upper and lower sealing elements are mounted in a common plunger assembly on each side of the elongated member, and wherein the upper and lower sealing elements on each side of the elongated member are driven by an individual actuator.

33. A method according to any of claims 30-32, characterized in that the elongated member is guided and centralized by guide arms which are provided in the respective piston assembly on each side of the valve.

34. A method according to any of claims 30-33, characterized in that the elongated member is received in a longitudinal passage hole, and wherein the left and right piston housings of the longitudinal passage hole in the form of piston side holes they intersect with the through hole, and where the left and right piston housings house the respective left and right piston assemblies that move inside the plunger holes in a common plane perpendicular to the through hole to open or seal the valve device ..

35. A method according to any of claims 30-34, characterized in that the sealing elements are housed in plunger holes in the body, and wherein each plunger hole contains no more than one sealing assembly.

36. A method according to claim 35, characterized in that each plunger assembly has a pair of sealing elements, and wherein each of the sealing elements has a pair of seals in the form of inner seals on their radially inner surfaces, wherein the inner seals are supported against the elongate member to seal the through hole, and in the form of outer seals housed in a slot, and wherein the outer seals seal the ring between the piston holes and the piston mounts.

37. A method according to claim 36, characterized in that the inner and outer seals in each sealing element are connected to complete the seal when the sealing elements are actuated.

38. A method according to any of claims 30-37, characterized in that a portion of the actuator accepted by a channel between the upper and lower sealing elements at a radially outermost end of the piston assembly is restricted within the channel, and where any of the two sealing elements moves independently of the other in the piston assembly, in relation to the actuator, while the other remains stationary and coupled with the captive portion of the actuator.

39. A method according to any of claims 30-38, characterized in that the sealing elements are captive in the piston holes and are restricted to move only parallel to an axis of the holes, which is coincident with a longitudinal axis of the movement of the actuator during the drive.

40. A method according to any of claims 30-39, characterized in that grease is injected into the axial space between the sealing elements to close the leakage routes.

41. A method according to any of claims 30-40, characterized in that the upper and lower sealing elements move relative to each other in response to a pressure differential applied to the upper and lower sealing elements, respectively.